Various mobile equipment exists for dispensing a wide range of fertilizers onto lawns, gardens and fields. Of particular interest with respect to the present application is fertilizer spreading apparatus of the type commonly referred to as a manure spreader, which as its name implies is typically used to spread animal wastes, such as barnyard manure. In a typical farm operation, manure is hauled from a confined holding area and dispensed as fertilizer onto fields where crops are to be grown. To this end, a variety of manure spreaders have been developed over the years to haul and distribute different types of manure. For instance, conventional box spreaders are preferred for handling dry, clumpy types of manure.
Box spreaders, well known in the agricultural implement art, include a box-like container having a conveyor moveable along the floor for transferring the material to the rear of the box. Rotating beaters, typically paddle shaped, are mounted in a transverse fashion at the rear of the box to engage and break up the material that has been conveyed rearwardly. The paddles also serve to distribute the broken up material in a swath as the spreader is transported across the field.
Even though box spreaders have proven to be effective for dry, clumpy manure, they have not been as effective for transporting and distributing manure having a significant liquid content. One problem is that box spreaders are not sealed, resulting in leakage when liquid or semi-liquid is being transported to the field, which in many instances is over publicly traveled roadways. To overcome this and other problems encountered with respect to the handling of liquid types of manure, spreaders have been developed in which the material is held in a leak resistant container.
In one common design the container is a tank having a cross section that is generally V-shaped with inwardly angled sides for guiding the material to an auger assembly mounted in the bottom thereof, which in turn conveys the material to a distribution assembly for discharge from the tank. This type of spreader, as opposed to a box spreader, is commonly referred to as a tank spreader and is well adapted for handling cattle manure in liquid or slurry form as well as other types of manure such as swine and poultry manure.
In tank type spreaders, there are various arrangements employing either one or two augers for moving the material to the discharge area. A typical example of a single auger machine is shown in U.S. Pat. No. 5,221,049, issued Jun. 22, 1993 in the name of Gilbert W. Linde, et al. In this spreader a single auger in the bottom of the tank conveys material to a distribution assembly that expels material out the side of the tank. The spreaders described in the following paragraphs all relate to double auger machines.
In U.S. Pat. No. 5,386,943, issued Feb. 7, 1995 in the name of Kenneth J. Peters, a dual auger arrangement is depicted in which a transverse beater type expeller is mounted above the augers to engage material as it is urged rearwardly by the augers. In U.S. Pat. No. 5,199,638, issued Apr. 6, 1993 in the name of Thomas R. Fischer, and U.S. Pat. No. 5,275,335, issued Jan. 4, 1994 in the name of Stanley W. Knight, et al, dual augers, rotating in the same direction, are utilized in a cooperative manner to convey material to a side discharge assembly. In the '335 patent one auger is mounted above the other, while in the '638 patent the augers are mounted in a side-by-side fashion at the same elevation. In still another representative prior art machine, dual augers are shown in U.S. Pat. No. 5,435,494, issued Jul. 25, 1995 also in the name of Stanley W. Knight, et al. In one embodiment of the '494 machine the augers are counter rotating and have different diameters, one of which is used as a feed auger and the other of which is used as a discharge auger.
In another type of prior art tank spreaders, dual augers urge material to expellers that are mounted for rotation about rearwardly located horizontal shafts. Exemplary of this combination are U.S. Pat. No. 3,871,588, issued Mar. 18, 1975 in the name of John B. Long, et al, U.S. Pat. No. 4,124,166, issued Nov. 7, 1978 in the name of Gustave Lucas, and U.S. Pat. No. 4,801,085, issued Jan. 31, 1989 in the name of Thomas R. Fischer.
In yet another arrangement wherein dual augers urge material rearwardly for discharge, expellers are mounted to rotate about vertical axes. Typical of this latter arrangement, is U.S. Pat. No. 5,501,404, issued Mar. 26, 1996 in the name of Donald A. Meyer, et al, which in the principal embodiment shows rotary expeller means with blades extending from a vertical shaft mounted rearwardly and external of the tank.
Another example of the latter arrangement is an early U.S. Pat. No. 2,296,909, issued Sep. 29, 1942 in the name of Merrills L. Dake, showing a truck mounted spreader used for spreading granulated material, such as salt, sand, or the like. In this spreader the augers, mounted within a flat bottomed tank, are counter rotating to discharge the material through an opening in the back wall of the tank onto distribution discs rotating about vertical shafts.
Notwithstanding the numerous kinds of spreaders available for transporting and discharging slurry type manures that are somewhat liquid in consistency, applicants have embraced additional needs for a reliable spreader that effectively spreads manure in a desired pattern on the field. More particularly, applicants have determined that the general need exists for spreading material, having a range of liquification from a sticky type pen manure to a wetter type, such as municipal sludge, without disruption of operation regardless of weather conditions. The below described apparatus is a new and useful solution, not heretofore devised, to these problems that addresses these needs.